Add a Loader class for loading tests from files.

test/loader_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library unittest.loader;
+
+import 'dart:io';
+
+import 'package:path/path.dart' as p;
+import 'package:unittest/src/loader.dart';
+import 'package:unittest/src/state.dart';
+import 'package:unittest/unittest.dart';
+
+import 'utils.dart';
+
+Loader _loader;
+String _sandbox;
+
+final _tests = """
+import 'dart:async';
+
+import 'package:unittest/unittest.dart';
+
+void main() {
+  var declarer = Zone.current[#unittest.declarer];
+  declarer.test("success", () {});
+  declarer.test("failure", () => throw new TestFailure('oh no'));
+  declarer.test("error", () => throw 'oh no');
+}
+""";
+
+void main() {
+  setUp(() {
+    _loader = new Loader(packageRoot: p.join(packageDir, 'packages'));
+    _sandbox = Directory.systemTemp.createTempSync('unittest_').path;
+  });
+
+  tearDown(() {
+    new Directory(_sandbox).deleteSync(recursive: true);
+    return _loader.close();
+  });
+
+  group(".loadFile()", () {
+    var suite;
+    setUp(() {
+      /// TODO(nweiz): Use scheduled_test for this once it's compatible with
+      /// this version of unittest.
+      new File(p.join(_sandbox, 'a_test.dart')).writeAsStringSync(_tests);
+      return _loader.loadFile(p.join(_sandbox, 'a_test.dart'))
+          .then((suite_) => suite = suite_);
+    });
+
+    test("returns a suite with a name matching the file path", () {
+      expect(suite.name, equals(p.join(_sandbox, 'a_test.dart')));
+    });
+
+    test("returns tests with the correct names", () {
+      expect(suite.tests, hasLength(3));
+      expect(suite.tests[0].name, equals("success"));
+      expect(suite.tests[1].name, equals("failure"));
+      expect(suite.tests[2].name, equals("error"));
+    });
+
+    test("can load and run a successful test", () {
+      var liveTest = suite.tests[0].load(suite);
+
+      expectStates(liveTest, [
+        const State(Status.running, Result.success),
+        const State(Status.complete, Result.success)
+      ]);
+      expectErrors(liveTest, []);
+
+      return liveTest.run().whenComplete(() => liveTest.close());
+    });
+
+    test("can load and run a failing test", () {
+      var liveTest = suite.tests[1].load(suite);
+      expectSingleFailure(liveTest);
+      return liveTest.run().whenComplete(() => liveTest.close());
+    });
+
+    test("throws a nice error if the package root doesn't exist", () {
+      var loader = new Loader();
+      expect(() => loader.loadFile(p.join(_sandbox, 'a_test.dart')),
+          throwsA(isFileSystemException(
+              "Directory ${p.join(_sandbox, 'packages')} does not exist.")));
+    });
+  });
+
+  group(".loadDir()", () {
+    test("ignores non-Dart files", () {
+      new File(p.join(_sandbox, 'a_test.txt')).writeAsStringSync(_tests);
+      expect(_loader.loadDir(_sandbox), completion(isEmpty));
+    });
+
+    test("ignores files in packages/ directories", () {
+      var dir = p.join(_sandbox, 'packages');
+      new Directory(dir).createSync();
+      new File(p.join(dir, 'a_test.dart')).writeAsStringSync(_tests);
+      expect(_loader.loadDir(_sandbox), completion(isEmpty));
+    });
+
+    test("ignores files that don't end in _test.dart", () {
+      new File(p.join(_sandbox, 'test.dart')).writeAsStringSync(_tests);
+      expect(_loader.loadDir(_sandbox), completion(isEmpty));
+    });
+
+    group("with suites loaded from a directory", () {
+      var suites;
+      setUp(() {
+        /// TODO(nweiz): Use scheduled_test for this once it's compatible with
+        /// this version of unittest.
+        new File(p.join(_sandbox, 'a_test.dart')).writeAsStringSync(_tests);
+        new File(p.join(_sandbox, 'another_test.dart'))
+            .writeAsStringSync(_tests);
+        new Directory(p.join(_sandbox, 'dir')).createSync();
+        new File(p.join(_sandbox, 'dir/sub_test.dart'))
+            .writeAsStringSync(_tests);
+
+        return _loader.loadDir(_sandbox).then((suites_) => suites = suites_);
+      });
+
+      test("names those suites after their files", () {
+        expect(suites.map((suite) => suite.name), unorderedEquals([
+          p.join(_sandbox, 'a_test.dart'),
+          p.join(_sandbox, 'another_test.dart'),
+          p.join(_sandbox, 'dir/sub_test.dart')
+        ]));
+      });
+
+      test("can run tests in those suites", () {
+        var suite = suites.firstWhere((suite) => suite.name.contains("a_test"));
+        var liveTest = suite.tests[1].load(suite);
+        expectSingleFailure(liveTest);
+        return liveTest.run().whenComplete(() => liveTest.close());
+      });
+    });
+  });
+}